Rusted exhaust studs!!!

[abumariah]

nothing makes me feel more amateur than trying to disassemble an old exhaust. and wouldn't you know it, i broke off two bolts in my exhaust manifold.

any suggestions? pretty please?

[philip]

KROIL by Kano Labs

I've used many different penetrating products against nature's locktite ... Kroil is the winner.

When I first replaced the thermostat on my SD, one or two of the water outlet bolts sheared off which required removal of the entire water outlet body to a shop having one of those plasma gizmos that melts out the bolt, leaving the parent thread intact.

BTW, I just got a call from the shop that serviced my clutch. Seems one of the two exhaust flange studs sheared off. They worked late into last night extracting the remainder and replacing the stud.

[asavage]

They break, and there's little you can do about it to prevent it. The studs just get too corroded. I feel your pain. However, you pretty much have to remove the manifold to do a good job of fixing it.

(click on any image for larger)


If you have a good acetylene torch, and enough nubbin to grab, you could try heating the manifold cherry and backing out the remaining stud, but I don't recommend it. Having done probably a hundred of these, I advise pulling the manifold, facing the broken studs off flat, center punching them, then drilling and helicoiling them.

Torch work in the engine bay often leads to heat damage of other parts. If the engine's pulled though, you may be able to remove them using heat and vise-grips. Don't bother with bolt extractors. And be very careful to center the center punch.

[ffdjm]

Al's advice regarding stud replacement works fine. With care the old stud can be drilled out and helicoil inserts installed. Usually studs break during exhaust pipe removal whilst forcibly unscrewing a seized on nut. I fixed that problem by using high temp anti-seize lubricant (the copper containing kind) between the stud and the nut. Also used self locking all metal nuts, which are more reliable than nuts and lock washers.

Douglas

[ecomike]

Well it looks like it's about to be my turn for this wonderful, fun, exciting little exercise. So I am wondering what all I should have on hand before I start disasembling everything, and where I should get it from. I am expecting the exhaust manifold stud bolts to break when I try to replace them. I figure If I am prepaired for the worst, then I might get luck with the pen lube and some patience.

Is Autozone an acceptable source for the I/E gasket(s?) Looking at the picture it seems to have a single common gasket for the intake and exhaust (thus I/E gasket) manifold.

Is there a good and bad quality gasket out there? How do I make sure I get the good one? Who has it? I have autozone, O'Reilys and Pepboys, and I forget the others, national chains nearby.

Should I replace the intake and exhaust bolts while in there, are they a standard size, if so what are they?

I see torq specs, but have not found the stud bolt specs in my FSM.

Any other surpises I should prepare for?

Anyone know if I will have to pull the A/C compressor to get the job done, the I/E gasket replacement that is?

Also, what is a reasonable price for a water pump for the SD-22? If I get to the point where I am pulling the A/C compressor out of the way, and if the water pump is not made of gold, I may just go for broke while in there.

[asavage]

Is Autozone an acceptable source for the I/E gasket(s?) Looking at the picture it seems to have a single common gasket for the intake and exhaust (thus I/E gasket) manifold.

NAPA FPG (Fel-Pro Gasket) MS91499 , $7

Is there a good and bad quality gasket out there?

OEM or Fel-Pro is my first choice. Victor (one of NAPA's lines) is second. I don't have a third choice in gaskets.

Autozone (I think) carries Fel-Pro as well.

Should I replace the intake and exhaust bolts while in there, are they a standard size, if so what are they?

They are a std size (8mm, I think). I replace the bolts that get hotter than 400°F, so manifold-to-headpipe automatically get replaced. The others are a case-by-case call. Don't put metric grade 8.8 back in, they're too soft.

Any other surpises I should prepare for?

If yours is like mine was (shown above), be prepared to have the manifold surfaced. Mine was extremely warped. I mean like over .060", no gasket will seal that.

[philip]

SNIP- Also, what is a reasonable price for a water pump for the SD-22? If I get to the point where I am pulling the A/C compressor out of the way, and if the water pump is not made of gold, I may just go for broke while in there.

Water Pump SD22

For the new "N" brand water pump, $85-$110. Don't waste the "GMB" part.

Be VERY slowly when removing tighly olding bolts. ANY bolts rusty ... replace.

[philip]

SNIP- If yours is like mine was (shown above), be prepared to have the manifold surfaced. Mine was extremely warped. I mean like over .060", no gasket will seal that.

Cast iron exhaust / iron cyl do eventually warp the exhaust when a "thickened" gasket. But if you remember ... 99% of ironed exhaust / iron cyl having a shim steel or ... NO shim at all ... keep a perfect iron exhaust match to the iron cyl.

(A.Savage)

[ecomike]

Well I checked O'Reilys and they have a Felpro gasket on its way in from their warehouse, $5.98. They were clueless on the manifolds and exhaust flange bolts. No data, not available. You say diesel and their computers go blank.

Is the exhaust flange bolt also an 8 mm? How do I figure out the stud bolt length ahead of time? Is there a standard length? Thread count? Should I try the nissan parts dealer?

Thanks for the warning on the warpage and on the GMB water pump.

I was reading recently in the Jeep forum a recomendation to use brass (I think?) bolts instead of steel, and not to use high strength bolts (as I recall) for exhaust manifold bolts. You mentioned 8.8 bolts being too soft, what do you recomend and why?

On the water pump, O'Reilys has a rebuilt water pump available for $41.99 by someone called A1 Cardon (?), they said new water pumps were not availble to them.

Should I even trust a rebuilt? Never mind, just read Philips posts and followed the trail (Nice!), I even found a NAPA store I never knew existed about 20 blocks from my house (well hidden, and off the beaten track), planning to buy the new "N" cast iron pump which I think is a No. NWP559198I. The NAPAonline.com has three pumps listed, one rebuilt, one new one is aluminum and a third that looks like the "N" cast iron pump, No. NWP559198 , which is the most expensive, $66.99. If it is the cast iron, for that small difference in price I will be getting a new one.

Nice pictures! They make me want to go work on my SD-22!

What is a "shouldered" bolt? I am sure I have seen and used them, just never ran across the term before and want to make sure what it is.

[kassim503]

Is the exhaust flange bolt also an 8 mm? How do I figure out the stud bolt length ahead of time? Is there a standard length? Thread count? Should I try the nissan parts dealer?

The exhaust flange studs looks to me like its M8x1.25, 1.25 thread pitch is the foreign equivalent of America's National Coarse. 1.75 thread pitch is the equivalent of National Fine Thread.

Metric grades go from 8.8, 10.9 and 12.9, there is probably more but I never been concerned with anything else, and metric grade 8.8 is comparable to the US's grade 5.

I was reading recently in the Jeep forum a recommendation to use brass (I think?) bolts instead of steel, and not to use high strength bolts (as I recall) for exhaust manifold bolts. You mentioned 8.8 bolts being too soft, what do you recommend and why?

Im not too sure if these are high or low strength, but I always used black oxide bolts, the ones that are black colored, lol its hard to explain them, they are bolts that are black

On the water pump, O'Reilys has a rebuilt water pump available for $41.99 by someone called A1 Cardon (?)......

I bought a WP from Cardon, for my now dying Chevrolet, and it had a stamped steel impeller, so they might market you a GMB style one if you ordered one for a Nissan. Not sure though, but im probably never gonna waste my monies on Cardone water pumps anymore.

What is a "shouldered" bolt? I am sure I have seen and used them, just never ran across the term before and want to make sure what it is.

A shouldered bolt is, look down one reply



Nice to hear you got your hands on a nice water pump, the N brand one would last you a good 150k easy

[asavage]

The exhaust flange studs looks to me like its M8x1.25, 1.25 threads per MM . . .

Nope, 1.25mm thread pitch. Distance between adjacent thread "tops". Not threads per millimeter. Also not at all like the SAE system.

. . . metric grade 8.8 is comparable to the US's grade 5.

Without Googling it, I think 8.8 is softer than GR5, which is why I don't use it for things that need significant torque.

Cardone is an economy brand. 'nuf said.

What is a "shouldered" bolt?

That shoulder bolt happesn to have a socket head, but the idea is the same for a hex head.



A lot of folks seem to be calling a bolt with a section of unthreaded shank a "shoulder bolt", which is incorrect. A shoulder bolt can be torqued tight without having any clamping force on the part fastened around the shouldered section.

I used to specify shoulder bolts a lot in a former life. Changed the way our job shop did certain jobs ("we've never done it that way before . . . "). Took me months to get shoulder bolts through the review process. I would make mine captive to removable guards, so you couldn't lose them.

[kassim503]

Nope, 1.25mm thread pitch. Distance between adjacent thread "tops". Not threads per millimeter.

My bad, thats what I meant, but I cranked out that reply at 1:30 in the morning so I guess "threads per MM" and the distance from major diameter to major diameter seemed the same.

[ecomike]

OK, the shoulder bolt is one I never would have guessed right! Thanks. Amasing the little things one can miss. I use to supply metal finishing equipment to the nut and bolt manufacturers here and thought I new a few things about bolts.

[asavage]

Well metric and SAE have nothing to do with eachother, but I was just comparing it to NC and NF because metric bolts are generally found in those thread pitches

There exist common metric diameters that have three or more different pitches. For example, the most commonly seen pitch for 8mm dia. is 1.25mm, but if you check out McMaster-Carr's metric tap page, you'll see four pitches listed for 8mm dia.: 0.5, 0.75, 1.00, 1.25 . I have run into applications that require a pitch not commonly stocked like this.

8.8 is softer than grade 5? had to google it, yeah its weaker, but just by a little, I dont think itll make a difference in most apps.

While 5% difference isn't much, my experience has been that the "8.8" class of fasteners found in my neck of the woods seem (by feel, mind you) to snap off much easier than an equivalent torque applied to an equivalent GR5 fastener of equivalent diameter -- like 8mm vs. 5/16". 5% may not seem like much on paper, but is seems like much out where the wrench meets the bolt. I buy 10.9 when a choice is available, just as I don't use GR2 where I can buy GR5.

[ecomike]

Well I have collected all the hardware for this. Now I just need a good ROUNDTOIT day with no rain and no fires to put out, LOL.

Got the studs in black iron, 40 and 45 mm long, 1.25 mm pitch, 8 mm dia., no idea what strength, only found one stock source and non of the ones I found had a stength listed for these. They were for exhaust pipe flanges and manifolds. I did manage to get brass nuts and copper aircraft style lock nuts. I may use the copper ones, but for now I have a choice.

Still worried about the water pump bolts, put I don't know what size to pre-order, so that will be a last minute purchase.

Hopefully this will go pretty smoothly.